Newbie question regarding Protein Skimmer.

Ok, here goes my first official question on this site. I have a sealife Systems skimmer that was given to me with the rest of the setup. Only problem I have is that my venturi (Air intake) is shooting water out instead of sucking air in. Now I don't know if the little air intake piece on the side of the PVC pipe near the top is supposed to have a hose with some kind of check valve or something. If it does then I'm missing it and need to find out where to get it.

My Skimmer is very similar to this one:


Thanks for any help.

 

Try this:

Sealife Systems Instruction Manuals